Diabetes continues to be the leading causes of kidney disease in the U.S. and around the world. The pathogenesis of diabetic kidney disease remains poorly understood. Despite beneficial interventions implemented in patients with diabetes that mitigate some of its negative effects, kidney disease still progresses in most of these patients. Recent evidence indicates that impairments in mitochondrial dynamics and function plays an important role in diabetic kidney disease and brings promise to treatment strategies for improving mitochondrial function and the related pathways that may prevent or slow the progression of kidney disease. In this proposal, we aim to determine the mechanisms and novel signaling mechanisms of SIRT3 and ERR-? in the prevention and treatment of diabetic kidney disease, mitochondrial dysfunction, and podocyte injury. In Specific Aim 1, we will determine how the mitochondrial sirtuin SIRT3 modulates diabetic kidney disease, including by regulating mitochondrial function and dynamics, and activating novel signaling pathways determined by quantitative phosphoproteomics and acetylomics. In male and female mice with i) podocyte specific SIRT3 knockout, or ii) transgenic overexpression of SIRT3 in podocytes, or iii) treated with a SIRT3 agonist, or iv) in podocytes grown in culture following SIRT3 overexpression or SIRT3 agonist treatment we will determine the effects on mitochondrial function and progression of kidney disease. We will also perform quantitative phosphoproteomics and acetylomics to determine novel signaling pathways that will be further explored for mechanistic studies related to SIRT3 action in the kidney. In Specific Aim 2, we will determine how the nuclear receptor ERR-? modulates diabetic kidney disease, including by regulating mitochondrial function and dynamics, and activating novel signaling pathways determined by quantitative phosphoproteomics and acetylomics. In male and female mice with i) podocyte specific ERR-? knockout, or ii) transgenic overexpression of ERR-? in podocytes, or iii) treated with a ERR-? agonist, or iv) in podocytes grown in culture following ERR-? overexpression or ERR-? agonist we will determine the effects on mitochondrial function and progression of kidney disease. We will also perform quantitative phosphoproteomics and acetylomics to determine novel signaling pathways that will be further explored for mechanistic studies related to ERR-? effects in the kidney.